Unparalleled Armour for Aramid Fiber with Excellent UV Resistance in Extreme Environment

Aramid fibers are widely used in many cutting-edge fields, including space, aviation, military, and electronics. However, their poor UV resistance and surface inertness seriously hinder their utilization, especially in harsh environments. Here, a dual-layer ultrathin Al₂O₃-TiO₂ coating with a thickness of 70-180 nm is fabricated on aramid fibers by a modified atomic layer deposition (ALD) method. The tenacity of ALD-coated aramid fibers decreases only by ≈0.85% after exposure to intense UV light (4260 W m^-2) under high temperature (>200 ℃) for 90 min, which equals to continuous exposure to sunlight for about 17 500 days. The as-prepared aramid fibers also show excellent laundering durability, thermal and chemical stabilities. This work presents a green and damage-free approach to achieve the highly anti-UV aramid fibers without sacrificing their outstanding performance, which is expected to guide material design for future innovations in functional fibers and devices.